This invention concerns a vacuum mower. By vacuum mower are understood all grass mowing devices that use an air stream, in whichever way, to support the mowing process. Vacuum mowers are conventional mowing devices, as e.g. the ones in DE B1 2643604. DE B1 2643604 shows a suction tube with an opening for the intake as well as one for the exhaust with a suction/blowing device which is able to suck the grass into the casing. According to DE B1 2643604 the device, contrary to other conventional mowers with rotating blades that operate parallel to the ground as, for example the U.S. Pat. No. 4,718,221, has the advantage that the angle between the opening for the intake and the direction of the growth of the grass can be altered. The mowing device for cutting the stems of the grass may be placed in front of the opening for the intake in the shape of a chaff cutting cylinder within a suction bell (column 1, lines 60-64), but it may also be built into the device directly at the intake in the form of a nozzle sucking up the grass (column 3, lines 63-64).
Chaff cutting cylinders are unshapely cylinders with a large number of cutting blades which are used only for a special mowing process of large areas. Their drives though, are heavy and cylinders serve for cutting the grass into small pieces rather than for cutting it off neatly. Placing the cutting device at one end of the suction tube while the other is mounted on a vehicle held above the ground by wheels, regardless of the contour of the ground below the cutting device, makes the construction somewhat difficult if you want to cut the grass at always the same height above the ground. The suction tube is rarely used for cutting grass on uneven terrain because it was mainly constructed for cutting bushes and shrubs at the side of the road, respectively for cutting grass on ground sloping down to the road. Such known devices are less suitable for universal use in gardens, parks or, for example golf courses.